Cephalcia tannourinensis Chevin
Taxonomic placing: Insecta, Holometabola, Hymenoptera, Symphyta, Pamphiliidae
Common name: Cedar webbing sawfly.
Geographical distribution: Lebanon.
Host plant: Cedrus libani Richard (Cedar of Lebanon).
Morphology: The adult has a flattened body, 7-11 mm long, with long antennae and narrow wings which are almost transparent and with dark venation. The larva is green, with three pairs of legs on the thorax and a single pair of anal prolegs.
Life cycle: The adults appear in April-June, each female placing about 50 eggs on the needles of new buds. As they open, the larvae feed on them and cause their browning. A larva may consume several needles. The mature larvae drop to the soil wherein they enter into one of two types of diapause: annual and for several years, determined by the soil moisture and temperature. The pest has one annual generation, but cannot survive in sandy soils or in peat.
Economic importance: A new, major pest of C. libani, causing needle browning, defoliation and tree decline. Heavily infested forests turn brown, looking as if burnt. In Lebanon the rate of attack came to 70-80%. Such heavy infestations may cause the death of cedars.
Monitoring: Soil samples are examined for the presence of the prepupae; changes in their numerical values may predict outbreaks. Adults can be caught in yellow or sex-pheromone traps during spring, when they emerge.
Chemical control: IGRs applied from the air are effective against the pest.
Biological control: Indigenous Lebanese entomopathogenic nematodes tested in the laboratory killed all sawfly nymphs whereas an introduced strain killed only 77%. A naturally occurring isolate of the entomopathogenic fungus Beauveria bassiana (Bals.-Criv.) Vuill infected and killed up to 100% of eggs and larvae within 7 days in the laboratory.
Abdo, C., Nemer, N., Nemer, G., Jawdah, Y.A., Atamian, H. and Kawar, N.S. 2008. Isolation of Beauveria species from Lebanon d and evaluation of its efficacy against the cedar web-spinning sawfly, Cephalcia tannourinensis. BioControl 53: 341-352.
Lahoud, C.E. 2006. Physiological development of Cephalcia tannourinensis Chevin larvae as influenced by soil properties of cedar forests in Lebanon. American University of Beirut, Department of Plant Sciences, pp. 182.
Nemer, N., Kawar, N. S., Kfoury, L. and Frerót, B. 2007. Evidence of sexual attraction by pheromone in the cedar web-spinning sawfly. Canadian Entomologist 139: 713–721.
Nemer, N., El Beyrouthy, M., Lahoud, C., Mnif, W., Bashour, I. and Kawar, N. 2014. The influence of soil properties on the development of Cephalcia tannourinensis Chevin (Hym. Pamphiliidae) infesting the cedar forests in Lebanon. African Journal of Biotechnology 13: 4369-4381.
Noujeim, E., Rehayem, M. and Nemer, N. 2015. Comparison of indigenous and exotic entomopathogenic nematode strains for control of the cedar web-spinning sawfly, Cephalcia tannourinensis in vitro. Biocontrol Science and Technology 25: 843-851.
Rehayem, M. (and 6 co-authors) 2018. New insights in biocontrol strategy against Cephalcia tannourinensis, the principal insect defoliator of Lebanese cedars. Forest Science 10: 1093.